I have no love for the Rockefellers but where did you get that bit of information. If you said that the AMA limited MD production as an act of trade protection (which they effectgively do !) I would agree !
You will have to get this at the local library—amazing book—explains how the Rockefellers took control of modern medicine:
https://www.amazon.com/Your-Life-Their-Toy-Rackets/dp/B004433TMA